The present invention relates generally to systems and methods for calibrating or balancing low level luminance sources, and more particularly to an optical instrument for accurately calibrating and balancing low level luminances of lighted instrument panel displays.
Calibration, adjustment and maintenance of instrument and panel lighting within a vehicle operator control station (such as a modem aircraft cockpit) is often difficult because the instrument lighting is typically functionally grouped and controlled by a master dimmer circuit. Differences among various instruments and panels make it difficult to keep individual instruments within a group at the same luminance level over the entire variable range. For example, luminances of a bank of instruments balanced at about 1 fL (a dusk setting) may be totally unbalanced when set to 0.001 fL (a dark night setting). Existing instrument panel lighting systems having instrument luminance trim capability have no calibrated standard or standardized test procedure and are adjusted manually at night through iterative subjective visual adjustments or with the use of a portable photometer, which are time consuming and expensive procedures and are sufficiently imprecise as to prevent assessment of the compatibility of a lighting system used in conjunction with an infrared-sensitive night vision device (NVD) (e.g., night vision goggles).
The invention solves or substantially reduces in critical importance problems with existing luminance level comparator devices and methods as just suggested by providing a small, self-contained, calibrated, relatively low-cost unit that can be easily used by maintenance personnel to balance instrument and panel lighting equipped with light trimming capability. The invention may be used to evaluate the degree to which the lighting is compatible with NVD use. The selectable colors and luminance ranges permit balancing luminance levels to MIL-L-85762 specified levels (0.1 fL, green light for instruments and panels) and viewed with NVDs for possible interference (non-compatibility) with improper spectral characteristics.
The invention may be used for adjustment of any standard or NVD instrumented, low-light level illuminated vehicle operator control station within cars, trucks, tanks, ships, etc, and may find particular use by aircraft manufacturers to quickly balance cockpit illumination, and could be used on a factory assembly line as an economical, quick check/calibration of manufactured devices having self-contained adjustable lighting systems (e.g., lighted instruments or panels).
It is therefore a principal object of the invention to provide an instrument and method for optically calibrating and balancing low level luminance sources.
It is a further object of the invention to provide an instrument and method for the accurate optical calibration and balancing of low level instrument panel luminances within a vehicle operator station.
It is another object of the invention to provide an optical instrument and method for enhancing visualization of a lighted vehicle instrument and instrument panel display under low level luminance conditions.
It is yet a further object of the invention to provide an instrument for evaluating NVD compatibility with low luminance levels of lighted instrument panel displays.
These and other objects of the invention will become apparent as a detailed description of representative embodiments proceeds.